Circuit interrupter



July 18, 1939. a. N. LEMMON v CIRCUIT INTERRUPTER Filed Aug. 31, 1936 Patented July 18, 1939 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER Application August 31, 1936, Serial No. 98,629

15 Claims.

This invention relates to electrical circuit interrupters of the sort known as expulsion tube fuses.

One purpose is to provide a device in which the tube is automatically removed from closed-circuit position whenever the fuse-link has ruptured. Another purpose is to provide means for readily removing and replacing the tube and its fuselink. Another purpose is to provide means for mounting such protective equipment directly on a transformer bushing, or similar location, with a minimum or strain upon such support. Another purpose is to provide an article of manufacture which accomplishes the desired results and which can be produced at low cost. Other purposes will be evident from the following specification and claims.

Referring to the drawing, Fig. 1 shows my device as mounted on a transformer; Fig. 2 is a partial view showing the hinge and the tube when the tube is being removed or replaced; Figs. 3, 4, and 5 are details of the hinge in partial section; Figs. 6 and '7 are similar details at the latch end of the tube; Fig. 8 is a modified form of hinge; and Fig. 9 shows in small scale a modification of the supporting insulators and other parts.

The transformer I has a porcelain bushing 2, and a terminal stud 3 upon which is mounted the circuit interrupter base 4. The bolt 3" clamps base 4 to stud 3. The base 4 supports the insulator 5 to which is secured the arm 8, with its pivoted latch 1. The base 4 also supports the hinge member 8 by means of the pivot 9.

A spring Ill biases hinge member 8 counterclockwise. The tube II has a hinge terminal l2 which engages with the hinge member 8, and a latch terminal l3 which carries a pivoted hook member 20 which is engageable with the latch l. A fuse-link l4 normally closes the circuit between hinge terminal i2 and latch terminal IS. The incoming line l5 connects with the rod l6, and the circuit extends through the members 6, l8, l4, l2, 8 and I to the transformer terminal 3. A flexible shunt ll makes positive connection between hinge member 8 and base 4.

Oneend of the fuse-link i4 is attached by the I screw 18 to the terminal I2, and the other end of i4 is held by screw- I9 to the hook 28. A curved spring 2| is supported by the arm 8 and presses upwardly against the terminal l3 to insure good contacts. The terminal I3 has a ring for engagement by a switch-hook 23 as shown in Fig. 2.

On thehinge member 8 are two projections as shown particularly in Figs. 2, 3, 4 and 5, which are engageable with the upper edges of the flared p ning which extends through terminal l2. A spring 22 biases the latch l counter-clockwise, and a suitable stop prevents overtravel.

Operation is as follows. To place the tube and its fuse-link in service, a switch-hook 23, or other suitable means, is used to lower the terminal l2 over the point of the hinge member 8 as shown in Fig. 2. The wide flare on i2 makes it easy to be so placed, and the parts are coordinated so that they readily become closely engaged with one another as shown in Fig. 5. The terminal I3 is next moved forward and downward, which causes the back, or upper, ridge on hinge 8 to engage with the edge cf I2, as shown in Fig. 3. Further motion of the tube towards closed position imposes more stress on the spring Ill, which retains the parts thus locked together until they return to their former positions. When the latch terminal l3 reaches closed position, shown in Fig. 6, it has engaged with the spring-contact 2i and the latch I engages with the hook 20, thereby holding the tube in closed circuit position, with a slight tension on the fuse-link l4. Flared upward projections on 8 serve as guides for IS.

When the fuse-link ll ruptures, as by overload, the hook 28 is free to rotate away from latch I to the position in which it is shown in Fig. 7. Then the spring l0 moves member 8 and so swings the tube II to the open position indicated by dotted lines in Fig. 1. The member 8 is prevented from over-travelling by the stop 8', but the momentum of tube ll carries it backward until the parts 8 and I2 are as shown in Fig. 4, when the lower, or forward ridge on 8 has engaged with the corresponding edge of the opening through hinge terminal l2. When it is desired to remove the tube from the device, the ring on I8 is lifted upwards, and a slight shaking of the switch-hook disengages hinge terminal I2 from both ridges on 8, so the upward removal of the tube may be completed. If it is-desired to open the circuit without rupture of the fuselink, a switch-hook or other suitable means is used to tap downwards on the extended part of the latch 1, thereby releasing it from the hook 20. The spring l8 thereupon swings the tube up to the opening position. Fig. 7 shows the latch 1 in the above position.

Fig. 8 shows a modified form of hinge in which the hinge member 24 has two slots between the portions 25 and 28, into which the terminal 26 fits. A flat projection 21 on each side of the terminal 26 engages with the said slots, and when the tube is pulled towards closed circuit position the projecting point 28 engages with 21 thereby locking together 24 and 26.

Locating the tube directly above the transformer terminal, reduces the strain imposed upon stud 3, and having the tube horizontal when the fuse ruptures prevents the gases from being expelled downward where they might cause trouble. Also it is possible to rotate'the entire protective device about the axis of the transformer terminal, thereby bringing the fuse tube into any desired angular position without moving the transformer.

Many modifications of mounting, hinge, latch, and other details can readily be made by one skilled in the art without departing from the purpose and spirit of this invention. Obviously any overload responsive means for interrupting the circuit within the expulsion tube, which is the equivalent for the fuse described above, may be substituted for the fuse and is within the scope of this invention.

As a modification, the hinge and latch ends of the device may be transposed so that the latch is mounted on the base arm 4 while the hinge is mounted on top of the insulator 5. It is also possible to provide a longer porcelain bushing for the transformer as shown in Fig. 9. In this case the arm 4 is'secured tothe bushing 2' by a band around the outside of the porcelain 2', and the terminal conductor 3 is connected directly to the member 6'. The incoming line I is attached to the arm 4, and the tube ll carries the fuse, similar to the arrangement shown in Fig. 1.

These and similar modifications do not depart from the purpose and spirit of this invention.

I claim:

1'. In combination, in a circuit interrupter, an insulating bushing with a conductor therethrough, two conductive members borne by the said bushing and insulated from one another and spaced from one another by a gap, a tubular insulating container above the said bushing and spanning the said gap, and a fusible conduct-or within the said container and completing the circuit between the said two conductive members.

2. In combination, in a circuit interrupter, an

' insulating bushing with a conductor therethrough, two conductive members borne by the said bushing, an insulating tubular container held transversely above the said bushing by the said conductive members, and a fusible conductor within the said container.

3. In a circuit interrupter, an insulating bushing with a conductor terminal at its upper end,

a second insulator supported upon the said terminal, a second conducting member supported upon the said second insulator, an arm' extending outwardly and upwardly from the first said terminal and a fuse completing the circuit between said second conducting member and the said arm.

- 4. In a circuit interrupter, an insulating bushing with a conductor terminal at its upper end, an arm secured to a mid-position on the bushing and extending outwardly to a second conducting terminal, together with a fuse membercompleting the circuit between the two said'ter'minals.

5. man apparatus of the class described, an

electrical device having a casing, an insulating bushing carried by said casing and forming a unitary portion of said casing, a fuse structure outside of said bushing for protecting said electrical device, and means detachably and removably locking said fuse structure to said bushing.

to bodily support said fuse structure from said bushing, whereby said fuse structure may be bodily removed from said bushing.

6. In an apparatus of the class described, an electrical device having a casing, an insulating bushing carried by said casing and forming a unitary portion of said casing, said bushing rigidly carrying a conducting member, a fuse structure outside of said bushing for protecting said electrical device, and conducting means forming a portion of said fuse structure detachably and removably interlocked with said conducting member, whereby said fuse structure is carried by said bushing and is bodily removable therefrom.

7. In an apparatus of the class described, an electrical device having a casing, an insulating bushing carried by said casing and forming a unitary portion of said casing, a stud rigidly carriedby said bushing, a fuse s'tructure outside of said bushing for protecting said electrical device, a socket member carried by said fuse structure for receiving said stud, and means detachably locking said socket member to said stud, whereby said fuse structure is supported from said bushing and is bodily removable therefrom.

8. In an apparatus of the class described, an electrical device having a casing, an insulating bushing carried by said casing and forming a unitary portion of said casing, a stud rigidly carried by said bushing, a fuse structure outside of said bushing for protecting said electrical device, a socket member carried by said fuse structure for receiving said stud, and means detachably locking said socket member to said stud, whereby said flue structure is supported from said bushing and is bodily removable therefrom, said stud and said socket member forming a portion of an electrical circuit to said electrical device.

9. In an apparatus of the class described, an electrical device having a metal casing, an insulating bushing carried by said casing, a dropout fuse structure supported from said bushing and including a pivotally mounted use tube movable from operative to inoperative position, mechanism normally holding said fuse tube in operative position and releasing said tube when said mechanism operates, and a fuse link restraining said mechanism from releasing operation.

' 10. Apparatus as set forth in claim 5, in which tube and permit the tube to move from its closedcircuit position.

12. Apparatus as set forth in claim '7, in which the fuse structure comprises a drop-out expulsion tube, means to hold the tube in operative position, and a conductor within the tube adapted operable on overload to break the circuit within the tube and permit the tube to move from its closed-circuit position.

13. In a circuit interrupter, an insulating bushing with a conductor terminal at its upper end, a second insulator supported 'uponsaid terminal, a

second conducting member supported on said second insulator, an arm extending outwardly and upwardly from the first said terminal, a drop-out expulsion tube, means to hold the tube in operative position, and a conductor within the tube completing the circuit between said second conducting member and said am and operable on overload to break the circuit within the tube and permit the tube to move from its operative position.

14. In a circuit interrupter, an insulating bushing with a conductor terminal at its upper end, an arm secured to the mid portion of the bushing and extending outwardly to a second bushing terminal, a drop-out expulsion tube, means to hold the tube in operative position and a conductor within the tube completing the circuit between said two terminals and operable on overload to break the circuit within the tube and permit the tube to move from its operative position.

15. In an apparatus of the class described, an electrical device having a metal casing, an insulating bushing carried by said casing, an expulsion tube circuit interrupting structure supported from said bushing and including a pivotaily mounted tube movable from operative to inoperative position, mechanism normally holding said tube in operative position and releasing said tube when said mechanism operates, and a conducting link operable to open the circuit in the tube and normally restraining said mechanism 15 from releasing operation.

. GEORGE N. LEMMON. 

